Strange Plumbing problem

[kevin_robson]

I have recently had a new bathroom suite installed.
The bath tap and feed for the toilet cistern both come from near each other from the same pipe. I will post some images later.

Everything works fine, apart from intermittantly when the toilet has flushed, the cistern doesn't fill up again afterwards. The solution is to flick the cold tap, and then the cistern starts filling instantly and works fine. The cistern is a concealed type in a cupboard from MFI.

It feels very much like a vacuum effect. Can anyone explain what could be wrong. The pipe layout is a single cold pipe running along the underneath of the bath with the cold tap coming off the end of it. Tee's come off before the end of the pipe for the toilet cistern and the shower, but the shower is still isolated.

Does it sound like faulty plumbing or faulty cistern. I had to replace the taps over the weekend as they were leaking, and it only seems to have done this since then. Could the new taps be a fault?

Thanks in advance

 

[dal5band]

I assume the cold is from a tank in the loft.
Do you have one of these new float valves in the toilet cistern ? They seem to require a bit of pressure to open the valve. When you open the bath tap it disturbs the valve just enough to get it going. Sounds like yours is just on the edge of being OK so you may be able to get it going with some adjustment of the level.

I think they come with a high pressure washer arrangemet and you can get a low pressure washer for some but only if you contact the manufacturer. In the old days, the valves had a low and high pressure nozzels included in the packing.

 

[kevin_robson]

Sorry - I should have mentioned that.
The cold water feed is from the mains, and seems to have plenty of flow and pressure.
I understand what you are saying about the pressure required to open the valve - it does feel like that - I'm just a bit confused about how opening the bath tap gets it going.

Cheers

 

[dal5band]

Don't know exactly but it's something to do with shock waves. The kind of thing that causes a water hammer if there is a loose pipe - the loose pipe jumps when you suddenly turn the tap on/off.

If you have mains - that normally blasts through everything, air-locks, sticking valves etc.
If you have easy access, try tapping the float valve in the loo cistern when it next happens.